Remove recycling HeadsUpManagerPhone objects

With this flag enabled HeadsUpEntry#mEntry could be non null.

Bug: 328390331
Test: atest AvalancheControllerTest BaseHeadsUpManagerTest HeadsUpManagerPhoneTest
Flag: ACONFIG com.android.systemui.notifications_heads_up_refactor DEVELOPMENT

Change-Id: I3a1cd242e22e46ce9f47406bdf78cf9192971faf
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index 79ae389..e1f6dbf 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -104,6 +104,13 @@
 }
 
 flag {
+    name: "notifications_heads_up_refactor"
+    namespace: "systemui"
+    description: "Use HeadsUpInteractor to feed HUN updates to the NSSL."
+    bug: "325936094"
+}
+
+flag {
    name: "pss_app_selector_abrupt_exit_fix"
    namespace: "systemui"
    description: "Fixes the app selector abruptly disappearing without an animation, when the"